In situ cleaning of diagnostic first mirrors: an experimental comparison between plasma and laser cleaning in ITER-relevant conditions
In situ cleaning of diagnostic first mirrors: an experimental comparison between plasma and laser cleaning in ITER-relevant conditions
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DOI：
10.1088/1741-4326/aa5d05
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发表时间：
2017-03
期刊：
影响因子：
3.3
通讯作者：
A. Maffini;L. Moser;L. Marot;R. Steiner;D. Dellasega;A. Uccello;E. Meyer;M. Passoni
中科院分区：
文献类型：
--
作者：
A. Maffini;L. Moser;L. Marot;R. Steiner;D. Dellasega;A. Uccello;E. Meyer;M. Passoni
本文对诊断第一镜 (FM) 的等离子清洗和激光清洗技术进行了实验比较。从托卡马克第一壁溅射到 FM 上的污染物的重新沉积可能会以一种不可接受的方式显着降低其反射率，从而影响等离子体诊断系统的正常运行。因此，需要合适的原位清洁解决方案来恢复 ITER 中的 FM 反射率。目前，等离子清洗和激光清洗被认为是最有前途的解决方案。在这项工作中，采用了一组类似 ITER 的铑镜，这些镜被专门用于再现托卡马克再沉积的材料污染，用于根据不同标准（反射率恢复、镜子完整性、时间要求）对等离子体和激光清洁进行实验比较。我们表明，这两种技术具有不同的互补特征，可用于 ITER FM 的清洁。特别是，等离子清洗可确保在紧凑污染物的情况下实现出色的反射率恢复，而激光清洗在多孔污染物的情况下更快、更温和、更有效。此外，我们还展示了结合等离子和激光清洗的协同解决方案的潜在优势，以充分利用每种技术的最佳功能。
This paper presents an experimental comparison between the plasma cleaning and the laser cleaning techniques of diagnostic first mirrors (FMs). The re-deposition of contaminants sputtered from a tokamak first wall onto FMs could dramatically decrease their reflectance in an unacceptable way for the proper functioning of plasma diagnostic systems. Therefore, suitable in situ cleaning solutions will be required to recover the FMs reflectance in ITER. Currently, plasma cleaning and laser cleaning are considered the most promising solutions. In this work, a set of ITER-like rhodium mirrors contaminated with materials tailored to reproduce tokamak redeposits is employed to experimentally compare plasma and laser cleaning against different criteria (reflectance recovery, mirror integrity, time requirement). We show that the two techniques present different complementary features that can be exploited for the cleaning of ITER FMs. In particular, plasma cleaning ensures an excellent reflectance recovery in the case of compact contaminants, while laser cleaning is faster, gentler, and more effective in the case of porous contaminant. In addition, we demonstrate the potential benefits of a synergistic solution which combines plasma and laser cleaning to exploit the best features of each technique.